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Serga [27]
3 years ago
5

Iron-59 has a half-life of 45.1 days. How old is an iron nail if the Fe-59 content is 25% that of a new sample of iron? Show all

calculations leading to a solution.
Chemistry
1 answer:
alexdok [17]3 years ago
4 0

Answer:  

90.2 da

Explanation:  

The <em>half-life</em> of iron-59 (45.1 da) is the time it takes for half the Fe to decay.  

After one half-life, half (50 %) of the original amount will remain.  

After a second half-life, half of that amount (25 %) will remain, and so on.  

We can construct a table as follows:  

  No. of    Time    Percent       Fraction

<u>half-lives</u>  <u>days</u>   <u>remaining</u>   <u>remaining </u>

      1           45.1         50                 ½

      2          90.2        25                 ¼

      3          135           12.5              ⅛

      4          180            6.25           ¹/₁₆

We see that 25 % remains after two half-lives or 90.2 da.

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Answer:

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Explanation:

7 0
3 years ago
A sample of gas at 310 Kelvin and 1.2 atmospheres has a density of 2.78 g/L. What is the molar mass of this gas?
Troyanec [42]
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5 0
4 years ago
Please answer both questions Thankyou
erma4kov [3.2K]

Answer:

The limiting reactant is oxygen gas and the reaction would produce 3.932 x 10 ^ 7 moles of water

Explanation:

Step 1: Convert everything into moles

nH2(l) = 1.06 x 10^8 g / 2.016 g/mol = 5.26 x 10^7 mols

nO2(l) = 6.29 x 10^8 g / 32.00 g/ mol = 1.966 x 10^7 mols

Step 2: Find the limiting reagent

The limiting reagent would be oxygen gas from

the balanced equation because we have less moles of oxygen gas needed to fully combust with the hydrant gas

Step 3: Stoichiometry time

The mole ratio from oxygen gas to water is 1:2

This means that for every mole of oxygen gas two moles of water is produced

We need to multiply the moles of oxygen gas by two to find out how many moles of water has been produced

nH2O = nO2 x 2

nH2O = 1.966x10^7 x 2

nH2O = 3.932x10^7

Step 4: Therefore statement

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7 0
3 years ago
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8 0
3 years ago
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The answer is D.
7 0
3 years ago
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